I've never seen that cover for annual #8 before. I think i would have been disappointed if i had bought it only to find early silver age art inside.
That being said the Annual #1 story was what cemented Subby being an awesome character for me. My first jump into Marvel comics was with FF masterworks vol. 1 in 2013. And the Sub-Mariner issues were easily my favorite. So by the time i got to Annual #1 in the essentials he was my favorite FF villain.